Sunday, March 30, 2014

Atmospheric carbon dioxide levels are measured at a number of different places around the world. One of the primary locations is atop the extinct volcano Mauna Loa on the island of Hawaii. This very remote location allows for a pristine atmosphere to sample, resulting in very good measurements. The level of CO2 in the atmosphere has been climbing on a continuous basis since the measurements were first taken in the the 1950s by Charles David Keeling. A plot of these results is now known as a Keeling curve and presents a characteristic saw-tooth pattern that results from seasonal changes in the CO2 concentration in the atmosphere.

The saw-tooth pattern is a result of the fact that CO2 levels drop in the summer when plants are awake to take the gas out of the atmosphere, but then rise in the winter when the plants go dormant. Last year the Mauna Loa CO2 measurements hit a milestone when they reached 400 parts per million (ppm), the highest ever recorded, at least so far. They have dropped over the summer, but they are now growing again. This is a plot of the last few years. Both the saw-tooth pattern and the rising trend can be easily seen here.

NOAA reports that the CO2 level in February 2013 was 396.80 ppm. The level for February 2014 was 398.03 ppm. I think the data shows it is inevitable that we will top 400 ppm this year.

Not that 400 ppm is so much more dangerous than 398 ppm. But, it illustrates the trend and how little we are doing to stop it. Since they started taking the measurements in 1958 at Mauna Loa, CO2 levels have risen approximately 25%. And, that is just the increase since 1958. There was an additional amount of increase before Keeling began taking measurements.

That data also shows the rate of increase is itself increasing. The average rate of increase over the 56 years of data is .45% per year. But, the rate of increase over the last 4 years is at .51% per year. So, not only is the problem bad, its getting worse.

Thursday, March 27, 2014

Climate change is frequently associated with some threshold that scientists refer to. For instance, a common threshold is a 2 degree Celsius rise in temperature over the pre-industrial level, which is cited as the threshold for dangerous changes in the climate. I have always had problems with these thresholds because they give the impression that the danger is way down the road and isn't anything we need to worry about today. That is a completely false impression to give. The changes are already happening and just because there are stages that won't occur until after the threshold doesn't mean we can't suffer from some changes right now.

An analogy would be declaring bankruptcy. You don't just wake up one morning and find your finances have so completely fallen apart you need to seek protection with the court. No, things were falling apart for quite some time, getting progressively worse. At first, things weren't bad. Maybe you noticed that you had less and less spare money after paying the bills, but you were still OK. Then, more and more things happened. Maybe you were turned down for credit when you applied for it. Maybe your credit card was turned down at the restaurant. At first, it was once a month. Then, it was every week. Finally, it was every day. Then, you found out you didn't have enough money in your paycheck to pay the bills, not to mention buy groceries. How were you going to feed the kids? That is when you sit down and wonder, "How did I get in this mess?"

That is the situation with climate change. Things have started out slowly. A little warming, maybe a few more severe storms than we use to have. Over time, more and more things happen. Mountain snow gets less and less leading to drier months in the summer. More and more crops fail due to heat or are destroyed in more frequent severe storms. You go to the grocery store and are stunned to see the price of food. Droughts occur more often and last longer. Reservoirs that use to be full of water are now full of weeds. When it does rain it comes down so fast that the area is flooded, washing everything away. You notice your electric bill in the summer is going through the roof because you have to run the air conditioner so much. The list goes on, but it is still manageable. We haven't reached the crisis point yet.

But, some day, we will reach that crisis point. When we do, we will realize that we saw it coming for years and didn't do anything about it. We will all sit down and wonder, "How did we get in this mess?"

That is the danger with the thresholds. We need to educate the public that it isn't some switch that will be flipped some day. Instead, it is a gradual ratcheting up of the consequences of our actions and the ratchet will continue to get tighter until we take responsibility for our actions and do something about it.

This is something I have fought with for years now. So many deniers just want to say that we don't need to do anything because even the scientists say it is years down the road. So, it was with interest that I read a paper today about that very issue. "The difficult, the dangerous, and the catastrophic: Managing the spectrum of climate risks," by Amy L Leurs and Leonard S Sklar addresses this very issue and they discuss many of the same issues I just did.

But, they propose an alternative approach.

In their scenario they use two individuals with different viewpoints concerning a number of events that occur as a result of global warming. The plot of the two individuals' viewpoints is presented below.

Climate risk space. Conceptual map of climate risk perceptions held by
multiple stakeholders. Risks vary across a spectrum of severity and time
scale over which impacts may be realized with increasing global
temperature. Two hypothetical stakeholders (red and blue) may value
impacts differently (vertical position) and perceive impact likelihood
differently (box-line thickness). Four possible combinations are
illustrated.

Once we have the changes, there are three things we can do: mitigate, adapt or suffer. That leads to this plot:

Risk management quadrants. Conceptual map of options for managing
climate risks. Four distinct quadrants are defined by inherent limits to
mitigation (vertical, solid line) and adaptation (horizontal, dashed
line). Grey bands represent uncertainty. The size of the suffering
quadrant will depend on the extent (arrows) to which the full potential
of mitigation and adaptation are realized by climate policies.

Events will plot a certain way, illustrating the current risk. Then, those events will be replotted over time, reflecting the changing situation. They conclude by stating,

We argue that the notion of a single, global threshold of dangerous
climate change, has outlived its usefulness as a focus for the climate
discourse. In its place, we propose a new climate risk management
framework that incorporates the inherent limits to mitigation and
adaptation, and links scientific risk assessment with social values and
risk perceptions. This risk management quadrants framework overcomes the
problems with the dangerous threshold by restructuring the climate
challenge around minimizing collective suffering, rather than averting a
distant catastrophe.

I agree with their argument completely. We need to change the way we do business on this issue to make it clear to the public that we are not discussing changes that won't happen in our life times. These are things that are going on right now and are affecting everyone on the planet. I don't know if their proposal is the right way to do it, but it sounds interesting and is certainly a good start.

It isn't official yet, but it will be soon. The maximum extent of Arctic sea ice passed in the last week or two. Take a look at these two figures. The first is the daily Arctic sea ice extent as plotted by the National Snow and Ice Data Center. The second is the surface temperature in the Arctic region and was obtained from the Polar Portal. We can see from the first plot that the amount of ice extent is decreasing. Fluctuations are normal and expected, but the second figure shows that the surface temperature of the ice along the fringes is above freezing, so no new ice will be forming.

Unfortunately, it looks like bad news for the Arctic sea ice this year. There is a long melt season ahead of us, so nothing is for certain. However, we are starting off badly. The level of sea ice this year is significantly below the 2012 level. This is important for two reasons. The summer of 2012 led to the lowest level of Arctic sea ice ever recorded, and this level was much lower than anything measured before. The second reason the 2014 levels are significant is because there was a large rebound of Arctic sea ice last year - a 60% rebound. Many people have been hoping this rebound would lead to increased levels of ice going into the future and slow down the climate change effects occurring in the Arctic region. However, even with the big 60% rebound, we see the extent levels for this year are starting out much lower than in recent years.

Hopefully, the melt rate will be slow this summer and we won't see a recurrence of 2012, but I don't feel good about the chances.